Catalytic desulphurization of petroleum hydrocarbons and production of hydrogen therefrom



United States Dec DESULPHURIZATION OF "PETRO- LEUMJ'HYDROCARBONS AND' PRODUCTIONOF HYDROGEN THEREFROM 'Iohn Arthur Edgar Moy and John Rowland, .Sunbury-on- Thames, England, amignors .to-T'Ihe British Petroleum Company Limited, London, "England, :a British. jointitoclr corporation NoTDrawing. ApplicationMarc'hT-2L1956 .SerlalfNo. 572,784

Claims priority, application Great Britain March22, .1955

This. invention relates 'to the catalytic desulphurization of petroleum hydrocarbons by "means *of "the :auto'fining process, the nature of which is fully :describcdinterzalia in United "States .Patents Nos. 2,573,726, 12,574,445-551 and T2;640;802. As .set 'forth in these :patents the autofining operation ?is "carried :out under a "temperature :se-

.lected between about 650"'-800 F. :and 2a :pressure selected '=betw.een T 500 ip;s.'i. ga. "with the temperature and pressure being correlated with 'respect to one am other :to insure a net production of hydrogen.

fIn order .to achieve adequate desulphurization of the higher boiling petroleum :distillates, such .as gas oils,

it is generally necessaryto operate under the equilibrium pressure method described in United 'States "Patent :No. 2,648,623. The equilibrium rpressure obtainable with any particular feedstock depends 'upon :the particular catalyst-employed, the temperature and the space velocity. For :a given catalyst, temperature and space velocity, the equilibrium :pressure gradually falls from the maximum obtainable with fresh catalyst .to :a lower value,

with decrease in the 'catalystactivity. The catalyst enormallyemployedintthe operation of the autofiningprocess is 'ofthe :kindcomprising the oxides "of cobalt and molybdenum either :as such or in combined form incorporated with .a metal oxide support, 'usually alumina. .As

set forth 'in Patent 'No. 2,648,623 in equilibrium gpressure autofining, the temperature is selected between 650 800 and the pressure is permitted .to rise above 100 psi. ;ga. until the .amount of hydrogen produced equals the amount of hydrogen consumed at which point the system vis in pressure equilibrium.

It :has :now been found that even 'after a petroleum {feedstock has been autofined under equilibrium pressure conditions it is possible 'to produce .a "further quantity of hydrogen from the feedstock by subjecting :it to autofining conditions at .a fixed gpressure 'below its .equilibrium pressure. Very'little if any,rfurtherdesulphurizationxmay be effected, but the additional *hydrogen 'produeed can be used with advantage, for-example, forother hydrofining operations in the'refinery.

' Accordingto the present invention therefore, :a petroleum distillate is subjected to :autofining under :equilibrium pressure conditions to eflect desulphurization 'of the distillate, and is thereafter again subjected 'to auto'finin-g conditions at a pressure below its "equilibrium pressure.

Either stage of the process accordingto the invention,

particularly thesecond'st-age thereof, may advantageously be :carried out over 'a :catalyst of the kind referred zto which has been "activated 'by the incorporation .therein of a 'small amount, preferably between 0.1% :and 6.0% by 'weight, of'fluorine, as describedin United States-application :No. 311,429, filed September .25, 1952, now Patent No. 2,800,429, granted July '23, 1957.

Pressure iRuterited flalune 52, 51 959 Thetinvention will'z now '"ibe :described' with reference .to itheifollowingaexamplez Example pressure conditions as *follows:

Catalyst 'Mlxell oxides rot zcobaltmnd' molybdenum :on ia'lumlna motivated with :alumlu- Temperature B0 :Spacevelolty... v. hr.

Recyclerrate..- 000 Lib. %(-set int'100%p:a.l.-;ga.1and

v n "varying with ressnre). essaazzzz: eatieee e "The feedstock .i'had the Toll'owingr'inspection data: 8.6. PI/'60 IF. 018435. IILBEP. (AS'ITM distillation) [248 (C. .FZBLP. :distillation) 360 TC. -Sulphur "content 126% Br. No. 33.7. Aromatics (AS'IM FD'SZ'S) i 1-'4'%" vo'l.

'The product (from lthis safter caustic ksoda and water washing had .;the following inspection fdata: .SL'G. 560 '-F./60' F. l. 0.58250. .IE-BEP. .(ASTM idistilla'tion) ZC. T'FJBP .(AS'FM :distillation) "3339' 5C. Sulphur-content 0;02% wr. PBroniine No. 7. 1., 9 Aromatics z'(-ASTM $13875), percent vol. 120.

This :pl'OdUCt was ;then reproeessedzuuder :the ifdllowing conditions: I f

Temperature 780 "Space velocity 52-v.'/-v.-/hr.

Recycle'rate Z2000 ci'fJB.

.40 hours.

Both fluOrineeprQmoted and 'sunpromoted ccatalys'ts *were used.

The results "were as ifollowsz Duration Weclaim:

1. A process for :the catalytic flesulphurization under autofin'in-g :conditions :or :a ppetroleum "distillate *and ".the production "of :hydrogen therefrom comprising contact- "ing .the distillate in 2a 'rreaction :zonewithsa "dehydrogenation-hydrogena'tion catalyst and Zhydrogen :derived solely from .the rdistillate sat a temperature between about 650 800 :and allowing .the :gpressute in said fzone i'tO rise to :an equilibrium pressure ;.above 2100 .p:s.i. ;ga. at which the hydrogen evolved :-:equals :.the lhydrogen sumed, recovering a distillate of reduced sulphur content, passing the recovered distillate through a reaction zone as the sole feedstock therein and in. contact with a dehydrogenation-hydrogenation catalyst at a temperature between about 6S0-800 F. and at a pressure below the equilibrium autofining pressure obtainable under the selected operating conditions employed in the desulphurizing reaction, recovering hydrogen from the products of reaction, and recovering a distillate having a sulphur content substantially equal to the sulphur content present prior to the second reaction.

2. A process according to claim 1, wherein the catalyst employed in the desulphurizing first stage comprises the oxides of cobalt and molybdenum incorporated with a support consisting essentially of alumina, the catalyst containing between 0.1% and 6.0% wt. of fluorine.

3. A process according to claim 1, wherein the catalyst employed in the second stage comprises the oxides of cobalt and molybdenum incorporated with a support consisting essentially of alumina, the catalyst containing between 0.1% and 6.0% wt. of fluorine.

4. A process according to claim 1, wherein the catalyst in both reaction stagescomprises the oxides of cobalt and molybdenum incorporated with a support consisting essentially of alumina, the catalyst containing between 0.1% and 6.0% wt. of fluorine.

5. A process according to claim 1, wherein the pc- 10 troleurn distillate is a gas oil.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PROCESS FOR THE CATALYTIC DESULPHURIZATION UNDER AUTOFINING CONDITIONS OF A PETROLEUM DISTILLATE AND THE PRODUCTION OF HYDROGEN THEREFROM COMPRISING CONTACTING THE DISTILLATE IN A REACTION ZONE WITH A DEHYDROGENATION-HYDROGENATION CATALYST AND HYDROGEN DERIVED SOLELY FROM THE DISTILLATE AT A TEMPERATURE BETWEEN ABOUT 650*-800* F. AND ALLOWING THE PRESSURE IN SAID ZONE TO RISE TO AN EQUILIBRIUM PRESSURE ABOVE 100 P.S.I. GA. TO WHICH THE HYDROGNE EVOLVED EQUALS THE HYDROGEN CONSUMED, RECOVERING A DISTILLATED OF REDUCED SULPHUR CONTENT, PASSING THE RECOVERED DISTILLATE THROUGH A REACTION ZONE AS THE SOLE FEEDSTOCK THEREIN AND IN CONTACT WITH A DEHYDROGENATION-HYDROGENATION CATALYST AT A TEMPERATURE BETWEEN ABOVE 650*-800* F. AND AT A PRESSURE BELOW THE EQUILIBRIUM AUTOFINING PRESSURE OBTAINABLE UNDER THE SELECTED OPERATING CONDITIONS EMPLOYED IN THE DESULPHURIZING REACTION, RECOVERING HYDROGEN FROM THE PRODUCTS OF REACTION, AND RECOVERING A DISTILLATE HAVING A SULPHUR CONTENT SUBSTANTIALLY EQUAL TO THE SULPHUR CONTENT PRESENT PRIOR TO THE SECOND REACTION. 